Oblique abdominal muscle activity in standing and in sitting on hard and soft seats

Abstract

The activity of the oblique abdominal muscles was investigated with the trunk in unconstrained, symmetrical and static postures. Electromyographic recordings in six healthy subjects revealed that in all subjects the activity of both the internal and the external obliques is significantly higher in unconstrained standing than in supine posture. Activity of the internal oblique was higher than that of the external oblique abdominal. The sacrospinal, gluteus maximus and biceps femoris muscles showed practically no activity in unconstrained erect posture. During unconstrained sitting both oblique abdominals are active. In most subjects the activity of the oblique abdominals was significantly smaller when sitting on a soft car seat than when sitting on an office chair with a hard seat. The possibility is discussed that contraction of the oblique abdominals in unconstrained standing and sitting may help in stabilizing the basis of the spine and particularly the sacroiliac joints. During standing and sitting the oblique abdominal muscles apparently have a significant role in sustaining gravity loads. RELEVANCE: Back pain and pelvic pain are often experienced in prolonged standing and sitting postures. In these postures the oblique abdominals are shown to be active. The present study gains clinical significance by the studies showing relatively small oblique abdominal muscle strength in patients with low back pain. A soft seat may be helpful in treatment and prevention, because it substitutes oblique abdominal muscle activity.

Trunk kinematics and muscle activities during arm elevation

“…There was no significant difference between right and left muscle activities in all trunk muscles in the resting standing posture. The percentage of the MVC in the IO activity in the resting standing posture was higher than in the other muscles, corresponding well to a previous finding [23]. In both slow and natural movements, only ES muscle activity was significantly enhanced, by approximately 1.5-fold, as compared with in resting standing posture.…”

Electromyographic activity of trunk muscles during exercises with flexible and non-flexible poles

“…In line with our results, Sánchez-Zuriága et al [22], also found more activation of IO muscle during exercises with an oscillatory blade while standing than while sitting upright. Perhaps, this result can partially be explained by the stabilizing effect of the IO on the sacro-iliac joints, in addition to its effects on the lumbar spine [23].…”

Lumbopelvic Kinematics and Trunk Muscle Activity During Sitting on Stable and Unstable Surfaces

“…3,29,36 sMVICs were generated for the abdominal muscles using the double leg raise movement due to its high reliability. 3,30 The participants were placed in supine, lying with hips flexed at 45°and knees at 90°.…”